Anthropology 1026F/G Lecture Notes - Machu Picchu, Melanin, Vasodilation

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Human Adaptation, Race/Ethnicity, and Sex/Gender
Human Biological Adaptation:
Plasticity: capacity to change physiologically in response to environmental stress
- Can be: physical environment (temp, exposure to sun, etc.) cultural
environment (available food, etc.)
- Flexibility to adapt humans have some capacity to adapt
Homeostasis: a condition of balance in a biological system dynamic steady state
Levels of Adaptation:
1) Genetic:
Allele frequencies in a population
Irreversible population wide
2) Ontogenetic:
Changes that one experiences while they’re growing
Individuals (rather than population wide)
Differential growth / development
Irreversible eg. volume of lungs, shape of organs (physical response to
environment – once you stop growing these changes are permanent)
3) Physiologic:
Acclimation: short term change (eg. tan)
Acclimatization: longer term change during lifetime (eg. athlete
competing at higher altitudes may go to the place early to adjust to the air
pressure etc. will go back to the way things were when they leave again)
Adaptations to Climate:
a) Bergmann’s Rule:
For mammals of the same shape
Generally – smaller animals lose more body heat
b) Allen’s Rule:
For mammals of the same size
More linear shape = lose more heat
c) Limb Proportion and Climate:
Cold climate: mammals have short limbs and stocky bodies
Hot climate (close to equator): mammals have long, slender limbs and
linear bodies
Adaptations to Heat:
a) Sweating:
Lose heat by evaporative cooling
Can lose too much! dehydration
b) Vasodilatation:
Capillaries at skin’s surface widen to allow increased blood flow lose
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Adaptations to Cold:
a) Shivering:
Generates body heat
BUT: requires energy
b) Vasoconstriction:
Restriction of capillaries / blood flow at skin’s surface
Keeps core protected
More efficient than shivering / heating up
BUT: danger of frostbite
Long-term: Inuit people cycle through vasodilatation and vasoconstriction retain heat
in core, then warm whole body again to avoid frostbite
Adaptations to High Altitudes:
a) Hypoxia:
Oxygen starving (>2400m – oxygen in air is getting thin and body feels
Physiological adaptation: more red blood cells
Ontogenetic adaptation: higher lung capacity
Developing children will grow larger lungs (will permanently stay with
them) – eg. in Machu Picchu – barrel shaped ribs (altitude changes lungs
which changes shape of ribs)
Adaptation to Malnutrition:
(Bad for children, and especially bad for fetus)
- Nutritional Status:
Dietary intake + work/activity + growth + repair (eg. ill – need more
intake) + storage
Undernutirion: poor quantity and quality
Impaired growth and development (for kids) – especially in stature
(won’t grow as tall as quickly)
*note: malnutrition can also be overeating
Variation in Human Biology:
- Relative homogenous species
- Polytypic Species: local variations in the expression of one or more traits
(traits are not always linked)
- Phenotypic Variation: 1000s of genes, 1000s of phenotypic outcomes
Interests in skin, eyes, hair (phenotypic traits that are easy to see):
certain phenotypes are more common in some populations
These traits follow Clinical Variation
- Clinal Variation:
Cline: gradual change in the frequency of genotypes and phenotypes
from one geographic region to another
Eg. blood types, skin colour
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